Straight Lines And Pair Of Straight Lines

If a line $L$ passing through the point $A(-2,4)$ makes an angel of $60^{\circ}$ with the positive direction of $X$ - axis in anti-clockwise direction and $B(p, q)$ lying in the 3rd quadrant is a point on $L$ at the distance of 6 units from the point $A$, then $\sqrt{p^2+q^2-8 q}=$